Characterization of d-glucaric acid using NMR, X-ray crystal structure, and mm3 molecular modeling analyses

d-Glucaric acid was characterized in solution by comparing NMR spectra from the isotopically unlabeled molecule with those from d-glucaric acid labeled with deuterium or carbon-13 atoms. The NMR studies provided unequivocal assignments for all carbon atoms and non-hydroxyl protons of the molecule. The crystal structure of d-glucaric acid was obtained by X-ray diffraction techniques and the structure was a close match to the low energy conformation generated from a Monte-Carlo-based searching protocol employing the mm3 molecular mechanics program. The molecule adopts a bent structure in both the crystalline and computationally generated lowest-energy structure, a conformation that is devoid of destabilizing eclipsed 1,3-hydroxyl interactions.